JPH10279754A - Graft polymer molding composition reduced in production of deposit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition for a high gross area, having extremely good processing technique characteristics without producing deposit during thermoplastic processing (treatment) by specifying a ratio of an amount of an additive to molecular weight of the additive. SOLUTION: This molding composition comprises (A) 5-95 wt.% at least one kind of thermoplastic homo-, co- or terpolymer of styrene, α-methylstyrene, etc., (B) 5-95 wt.% at least one kind of graft polymer of (ii) 5-90 pts.wt. styrene, α-methylstyrene, etc., on (i) 95-10 pts.wt. rubber having <=0 deg.C glass transition temperature and (C) 1-10 pts.wt. at least one kind of additive such as an internal lubricating agent or an antistatic agent and the component A is produced by mass, solution or suspension polymerization and has <=1% oligomer content and the component B is produced by emulsion polymerization and has <=0.8% total oligomer content in the objective composition and a ratio of an amount of the additive to molecular weight of the additive in the objective composition is <150.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a thermoplastic graft polymer for high gloss applications in which additives exuding from the thermoplastic composition during processing tend to decrease and deposit buildup in the mold is reduced. It relates to a molding composition.

[0002] Graft polymer molding compositions, especially ABS
The molding composition comprises: Thermoplastic copolymers of styrene and acrylonitrile in which styrene may be completely or partially replaced by other monomers, for example α-methylstyrene or methylmethacrylate [this copolymer also being terminated with SAN resin or matrix resin] Forms an external phase], and II. I. onto butadiene homo- or copolymers ("graft backbone") At least one graft polymer of the ABS type prepared by the grafting reaction of one or more of the monomers cited therein, said graft polymer ("elastomer phase" or "graft rubber") forming a dispersed phase in the matrix resin. It is a two-phase plastic.

[0003] One important aspect of the production of high gloss moldings from these molding compositions is that the growing requirements of the market for the absence of deposits in the mold (for example, the complete production of moldings by injection molding). Possibility of automatic plastic processing), as well as the reliable prevention of contamination on moldings due to the appearance of liquid or low-viscosity components, which is necessary for high gloss applications. Similarly, the sediment must not adhere to the grains of the granular part, as this results in an unsatisfactory transition to the part. On the other hand,
ABS molding compositions must exhibit optimal properties, especially with regard to their thermoplastic processability and viscosity, but this can often only be ensured by the addition of special additives, which are often liquid. it can.

[0004] It is therefore an object of the present invention to provide a graft polymer molding composition for high gloss areas having very good processing technical properties without the occurrence of deposit formation during thermoplastic processing. , Preferably an ABS molding composition.

[0005] When the molding composition is synthesized from specially made components, and there is a certain compatibility.
It has now been found that the requirements set out above are fulfilled if the liability) conditions are followed.

The present invention relates to: A) 5-95%, preferably 10-90%, and most preferably 20-75% by weight of styrene, α
B. B.-at least one thermoplastic homo-, co- or terpolymer of methylstyrene, acrylonitrile, N-substituted maleimide or mixtures thereof; 2) 95 to 10 parts by weight, preferably 70 to 20 parts by weight
B. on parts by weight of rubber having a glass transition temperature of ≦ 0 ° C. 1) 5-90 parts by weight, preferably 30-80 parts by weight of styrene, α-methylstyrene, acrylonitrile,
5-95 of the N-substituted maleimide or mixtures thereof
% By weight, preferably 10 to 90% by weight, and most preferably 25 to 80% by weight of at least one graft polymer, and C) 1 to 10 parts by weight, preferably 2 to 7.5 parts by weight, and most preferably From 3 to 5 parts by weight (in each case per 100 parts by weight of A + B) of at least one additive selected from the group consisting of internal lubricants, antistatic agents, mold release agents or mixtures thereof. A thermoplastic molding composition of the ABS type, wherein component A) is prepared by bulk, solution or suspension polymerization and is ≤1% by weight, preferably ≤0.75% by weight, and most preferably ≤0.5% by weight %), Component B) is synthesized by emulsion polymerization, and the total oligomer content (dimer, trimer, tetramer) of the molding composition is ≦ 0.8% by weight, preferably Or ≦ 0.7% by weight, and most preferably ≦ 0.
6% by weight and the ratio of the molecular weight of the additives in the molding composition to the amount of additives (in% by weight) does not fall below a value of 150, preferably 200 and most preferably 250. To a thermoplastic molding composition.

Polymers A) which are suitable according to the invention
Is ≦ 1% by weight, preferably ≦ 1% by weight, prepared by bulk, solution or suspension polymerization and not by emulsion polymerization
0.75% by weight, and most preferably ≦ 0.5% by weight
A resin-like, thermoplastic, rubber-free product of styrene, α-methylstyrene, acrylonitrile, N-substituted maleimide or mixtures thereof having an oligomer content of

Preferred polymers are styrene / acrylonitrile mixtures, α-methylstyrene / acrylonitrile mixtures, styrene / α-methylstyrene / acrylonitrile mixtures, styrene / N-phenylmaleimide mixtures, and styrene / acrylonitrile / N-phenylmaleimide mixtures. It is a polymer produced from.

[0009] Styrene / acrylonitrile copolymers and α-methylstyrene / acrylonitrile copolymers are particularly preferred polymers.

[0010] Polymer resins of this type are known. These resins must be manufactured so as not to exceed the required oligomer content. In the hot solution or bulk polymerization processes that are most frequently used industrially, oligomers are preferentially formed from 2 to 4 monomer units (in this regard, Makromol. Chem. 1 ).
77 (1976), pp. 2031-2042: styrene /
Oligomer formation in thermal copolymerization of acrylonitrile.
Developing K. Kirchner and H.M. Schlapko
hl). To prevent such oligomer formation, certain initiators, such as di-tert. −
Special reaction conditions must be used including the use of butyl peroxide, 1,1-bis (t-butylperoxy) cyclohexane, benzoyl peroxide or azo-bis-isobutyronitrile. Methods such as these are known (see, for example, US-PS 4,068,064).

Thus, the polymers A) which are suitable according to the invention are preferably those which use organic radical initiators and other reaction conditions which are possibly necessary in order to achieve a low content of oligomers, for example US-PS 4,068,
Produced by bulk, solution or suspension polymerization, maintaining the conditions stated in 064.

In principle, a further process for preparing polymers A) which are suitable according to the invention consists in bringing the oligomer-containing resin to the required oligomer content by a degassing step (for example in the melt). . However, this method is relatively expensive.

The oligomer can be measured by a conventional method. They are most commonly measured by gas chromatography or by gel permeation chromatography.

The resin component A) is preferably 20,000
Average molecular weight M _w of 0-200,000, or 20-11
It has a limiting viscosity [η] of 0 ml / g (measured in dimethylformamide at 25 ° C.).

Particularly suitable rubbers for preparing the graft polymers B) are polybutadienes, butadiene / styrene copolymers, butadiene / acrylonitrile copolymers, polyisoprenes or C ₁ -C ₈ -alkyl acrylates, in particular ethyl, butyl and ethylhexyl acrylate Is an alkyl acrylate rubber based on

Alkyl acrylate rubber is 30% by weight
Optionally, up to (in terms of rubber weight) monomers incorporated by copolymerization, such as vinyl acetate, acrylonitrile, styrene, methyl methacrylate and / or vinyl ether, may be included. They may also contain smaller amounts, preferably up to 5% by weight (based on the weight of rubber), of ethylenically unsaturated monomers which have a crosslinking effect and are incorporated by polymerization. Examples of crosslinking agents include alkylene diol diacrylate, alkylene diol dimethacrylate, polyester diacrylate and polyester dimethacrylate, divinylbenzene, trivinylbenzene, triallyl cyanurate,
Contains allyl acrylate and allyl methacrylate, butadiene or isoprene.

The acrylate rubbers used as graft backbones also include, at their core, bridged diene rubbers prepared from one or more conjugated dienes, such as polybutadienes, or conjugated dienes and ethylenically unsaturated monomers such as styrene and / or acrylonitrile. And a copolymer with

Preferred rubbers for the graft polymers B) are diene and alkyl acrylate rubbers. Polybutadienes and copolymers of butadiene and styrene and of butadiene and acrylonitrile are particularly preferred.

The rubber is at least partially bridged with an average particle size (d ₅₀ ) of 0.05 to 0.60 μm, preferably 0.08 to 0.50 μm, and most preferably 0.1 to 0.45 μm. It is present in the graft polymer B) in the form of particles which have been subjected to cross-linking.

The average particle size d ₅₀ is determined according to W.W. Scholtan
Et al., Kolloid-Z. u. Z. Polymer
e 250 (1972), measured by ultracentrifugation measurement according to 782-796.

The graft polymer B) is present in the form of an emulsion, the rubber B.R. Monomer B. in the presence of 2) It is produced by radical-induced emulsion graft polymerization of 1).

Suitable additives C) used according to the invention include internal lubricants, antistatic agents and release agents. These additives play an important role in achieving good surface quality. In this regard, these additives are from 1 to
It is used in an amount of 10 parts by weight, preferably 2 to 7.5 parts by weight, and most preferably 3 to 5 parts by weight (in each case 100 parts by weight of A + B).

Examples of internal lubricants include hydrocarbons (eg, paraffin oil, polyethylene wax), alcohols (eg, stearyl alcohol), carboxylic acids (eg, lauric acid, palmitic acid, stearic acid), carboxylic acid amides (stearic acid). Acid amide, ethylenediamine-bis-stearylamide), carboxylic acid esters (eg, n-butyl stearate, stearyl stearate, glycerol monostearate, glycerol tristearate, pentaerythritol tetrastearate), and preferred internal lubrication Agents are carboxylic amides and carboxylic esters.

Examples of antistatic agents include cationic active compounds (for example, quaternary ammonium, phosphonium or sulfonium salts), anionic active compounds (for example, alkyl sulfonates, alkyl sulfates, alkyl phosphates, alkali metals or alkaline earths). Carboxylates in the form of metal salts), non-ionogenic compounds (eg, polyethylene glycol esters, polyethylene glycol ethers, esters of fatty acids, ethoxylated fatty amines), and preferred antistatic agents are non-ionogenic compounds.

Examples of release agents include calcium stearate,
It contains zinc stearate and magnesium stearate, and the preferred release agent is magnesium stearate.

In this connection, in order to ensure a satisfactory reduction of sediment formation, (molecular weight of the additive added):
The ratio (amount of added additives in the molding composition in% by weight) should not fall below a value of 150, preferably 200, and most preferably 250.

Apart from the additives cited above, the molding compositions according to the invention may also contain stabilizers, pigments and fillers.

The mixture according to the invention can be prepared in a known manner
Mixing the components at the same time or one after the other at room temperature or at a high temperature,
And then in the melt at 150 ° C to 300 ° C
Conventional processing equipment at a temperature of e.g. internal kneaders, extruders,
Or by compounding or extruding in a twin shaft screw type device.

The molding compositions according to the invention can be used for the production of any type of molded article, and here customary production methods can be used. In particular, molded articles can be produced by injection molding techniques.

Another method for processing the molding composition according to the invention is the production of moldings by thermoforming from slabs or sheets produced by previously known methods.

[0031]

EXAMPLES Component A1: Di-tert. 14 with butyl peroxide
Styrene / acrylonitrile with an average molecular weight M _w of 88,000, prepared by suspension polymerization at 0 ° C. =
72:28 copolymer.

Oligomer content: 0.35% by weight.

A2: Di-tert. Styrene having an average molecular weight M _w of 81,000, prepared by cyclic bulk polymerization at 140 ° C. with -butyl peroxide
Acrylonitrile = 72: 28 copolymer.

Oligomer content: 0.60% by weight.

AV (comparative substance): average molecular weight M _{w of} 85,000, produced by hot bulk polymerization at 165 ° C.
Of styrene / acrylonitrile = 72: 28 having the following formula:

Oligomer content: 1.83% by weight.

B1: In the presence of 55 parts by weight (calculated as solid) of a polybutadiene latex having an average particle size (d ₅₀ ) of about 400 nm, of a monomer mixture of styrene and acrylonitrile (weight ratio = 73: 27) Graft polymer obtained by 45 parts by weight of potassium persulfate-initiated emulsion polymerization, coagulation with a magnesium sulfate / acetic acid mixture, and drying of the polymer powder.

B2: of a monomer mixture of styrene and acrylonitrile (weight ratio = 73: 27) in the presence of 55 parts by weight (calculated as solid) of a polybutadiene latex having an average particle size (d ₅₀ ) of about 130 nm Graft polymer obtained by 45 parts by weight of potassium persulfate-initiated emulsion polymerization, coagulation with a magnesium sulfate / acetic acid mixture, and drying of the polymer powder.

C1: Ethylenediamine-bis-stearylamide (Henkel KG, Duesseldor)
f, Germany) C2: n-butyl stearate (Merck AG, D
armstadt, Germany) C3: Magnesium stearate (Baerloche)
r, Munich, Germany) The components mentioned above are mixed homogeneously in the amount given in Table 1 in an internal kneader at about 190 ° C. to 200 ° C. and subsequently converted to a granular form.

This material was treated using a hot runner mold as illustrated in FIG. 1 under the conditions given below.

After 350 injection operations, the disk was removed and the amount of deposit was measured (see Table 1,
Last column).

It can be seen from these results that only the molding composition according to the invention resulted in very little deposit formation.

Processing conditions Injection molding machine: Kloecker-Ferromatik-FM 60, total control Worm diameter: 25 mm Mold clamping force: 600 kN Maximum charging weight: 45 g Maximum injection molding pressure: 3000 bar Mold: round disk, diameter 118 mm, thickness 2-4 mm, preferably 2 mm for hot runners (FIG. 1), double pinpoint gates with 6 interchangeable end disks, immersion seams and air ejectors (each with a diameter of 0.1-2 mm, preferably Each has a diameter of 0.8 mm), wall thickness 1.5 mm (variable), charging weight 20 g (disk 15 g, sprue 5 g).

Injection molding Parameters: Material temperature: 240 ° C. Mold temperature: 28 ° C. Warm advance speed: 100 mm / s Injection molding time: 0.5 s Average residence time: 143 s Full cycle: 35.5 s (pressure residence time: 12 s, cooling) Time 18 s, pause time 1 s) When injection molding these ABS molding compositions (FIG. 1), a special mold was used to measure the deposits formed in the mold. Round disk 7 (118 mmol,
2 mm thick) were produced in this mold by injection molding via two gates 1 (diameter 0.8 mm) according to the given processing conditions. As the hot material (240 ° C.) flowed into the cavity 2, a deposit 4 of volatile constituents was formed on a circular flow line that matched the center of the cavity. After these flow lines came into contact, the injection molding operation was stopped so that an area 6 nearly triangular remained for evaluation of the deposit (FIG. 2). This procedure corresponded to 80% of the total weighing distance of 80%. The amount of deposit was determined by removing the replaceable end disc 3 from the mold after 350 injection molding operations in each case and measuring its total weight (FIG. 2). An additional check of the weight was made by removing the sediment with a razor blade.

[0045]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a sectional view of a hot runner mold.

FIG. 2 is a schematic diagram including a substantially triangular area remaining for evaluation of sediment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gate 2 Cavity 3 Exchangeable end disk 4 Deposit 7 Disk

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 55/02 C08L 55/02 (72) Inventor Edgar Lights Germany 41541 Dolmagen Herrenbeek 25 (72) Inventor Heinrich Alberts Germany 51519 Odenthal Schillersche Trasse 1r (72) Inventor Thomas Etzkel Germany 41540 Dolmagen Pfauenci Jutras 51 (72) Inventor Deiter Bittmann Germany 51375 Leaf Erkusen Ern Str- Ludwig-Kirchner-Schjulase 41

Claims (5)

[Claims] 1. A) 5-95% by weight of styrene, α-
B) at least one thermoplastic homo-, co- or terpolymer of methylstyrene, acrylonitrile, N-substituted maleimide or mixtures thereof; 2) On rubber having a glass transition temperature of ≦ 0 ° C. from 95 to 10 parts by weight. 1) 5 to 90 parts by weight of at least one graft polymer of 5 to 95 parts by weight of styrene, α-methylstyrene, acrylonitrile, N-substituted maleimide or a mixture thereof; and C) 1 to 10 parts by weight (100 parts by weight) (A + B per part), an ABS-type thermoplastic molding composition comprising at least one additive selected from the group consisting of internal lubricants, antistatic agents, release agents or mixtures thereof, Component A) is prepared by bulk, solution or suspension polymerization and has an oligomer content of ≤1% by weight, component B) is prepared by emulsion polymerization and the total oligomer content of the molding composition is ≤0.8% by weight A thermoplastic molding composition characterized in that the ratio of the molecular weight of the additive to the amount of the additive (in% by weight) in the molding composition does not fall below a value of 150. 2. A) 10 to 90% by weight of styrene, α
B. B.-at least one thermoplastic homo-, co- or terpolymer of methylstyrene, acrylonitrile, N-substituted maleimide or mixtures thereof; 2) 70 to 20 parts by weight on rubber having a glass transition temperature of ≦ 0 ° C. 1) 30 to 80 parts by weight of at least one graft polymer of 10 to 90% by weight of styrene, α-methylstyrene, acrylonitrile, N-substituted maleimide or a mixture thereof, and C) 2 to 7.5 parts by weight ( (Per 100 parts by weight of A + B)
An ABS-type thermoplastic molding composition comprising at least one additive selected from the group consisting of internal lubricants, antistatic agents, release agents or mixtures thereof, wherein component A) is in bulk Is prepared by solution or suspension polymerization and has an oligomer content of ≦ 0.75% by weight, component B) is prepared by emulsion polymerization, the total oligomer content of the molding composition is ≦ 0.7% by weight, And the ratio of the molecular weight of the additive to the amount of the additive (in% by weight) in the molding composition is 200
2. A according to claim 1, characterized in that it does not fall below the value of
BS type thermoplastic molding composition. 3. The thermoplastic resin component A) comprises styrene /
3. The thermoplastic molding composition according to claim 1, wherein an acrylonitrile copolymer and / or an [alpha] -methylstyrene / acrylonitrile copolymer are used. 4. For the production of a molded article by injection molding,
Use of the thermoplastic molding composition according to any one of claims 1 to 3. 5. The use of a thermoplastic molding composition according to claim 1 for the production of high-gloss molded articles.